More about properties of Morse oscillator

[Display omitted] •Use of either De or xe for evaluation of Morse potential yields different results.•The Morse parameter “a” depends on the range used for Birge-Sponer approximation.•Deviations from linear Birge-Sponer plot reveal properties of the chemical bond. Using Birge-Sponer extrapolation we have analyzed the approximation of the potential of a real diatomic molecule by the Morse model, which implies a constant value of anharmonicity ωx. The real values of ωx*(v) for each vibrational level are estimated from transition frequencies between neighboring levels. The dependence of ωx* on the vibrational quantum number v up to dissociation is calculated from the literature data for the ground electronic state of H2, O2, Be2, Li2, ArXe, Xe2, Kr2 and the excited state of Li2. Characteristic features of deviations of the anharmonicity parameter x* - x from the Morse model are described.